Astronomy, Astrophysics, Cosmology Forum

Post thread
Join in expert discussion on the topics of Astronomy, astrophysics and cosmology. This may include discussion on celestial objects, space, and the physical universe as a whole. Mainstream science only.
High School Exoplanets - Suspicious evidence and fantastical conclusions
  • · Replies 21 ·
Replies
21
Views
6K
Stargazing Astro Image Stacking (optimize DSS image stacking and post processing)
  • · Replies 43 ·
2
Replies
43
Views
12K
Undergrad Theory behind how expansion moves mass but doesn't interfere with inertia?
  • · Replies 21 ·
Replies
21
Views
3K
Graduate Lagrangian vs pseudo-Lagrangian vs Eulerian
  • · Replies 1 ·
Replies
1
Views
4K
High School Why didn't the Moon go fully red for this eclipse?
  • · Replies 8 ·
Replies
8
Views
3K
High School Is There a Reference Point for the Expansion of the Universe?
  • · Replies 3 ·
Replies
3
Views
2K
High School Comoving distance in cosmology
  • · Replies 1 ·
Replies
1
Views
2K
High School Hyperloop - Orbital Space Launch
  • · Replies 28 ·
Replies
28
Views
6K
High School Earth from Space: What Would Hubble See?
  • · Replies 2 ·
Replies
2
Views
3K
High School Do Black holes reach a critical mass?
  • · Replies 3 ·
Replies
3
Views
3K
High School Could Solar Radiation Explain 'Oumuamua's Strange Trajectory?
  • · Replies 6 ·
Replies
6
Views
3K
High School The Hubble WFC3 instrument has stopped working
  • · Replies 2 ·
Replies
2
Views
2K
Undergrad Supermassive black hole eating a stellar black hole
  • · Replies 2 ·
Replies
2
Views
3K
High School Skydiving from Space -- maximum altitude?
  • · Replies 13 ·
Replies
13
Views
17K
Graduate Hot dark matter constrained by the CMB
  • · Replies 7 ·
Replies
7
Views
3K
High School Missing Dark Matter of NGC1052-DF2
  • · Replies 1 ·
Replies
1
Views
1K
High School How high can a helium baloon rise to space?
  • · Replies 18 ·
Replies
18
Views
13K
Undergrad Would it be possible to observe an alien city?
  • · Replies 6 ·
Replies
6
Views
2K
Undergrad Why does an Empty Universe have to obey Negative Curvature?
  • · Replies 10 ·
Replies
10
Views
3K
Undergrad How to find the position of a celestial object in the sky?
  • · Replies 2 ·
Replies
2
Views
3K
Undergrad What is the mass of all photons emitted in the universe?
  • · Replies 13 ·
Replies
13
Views
3K
High School Are White Dwarves Turning into Galactic Disco Balls?
  • · Replies 1 ·
Replies
1
Views
2K
Undergrad What does this description mean? (two bodies orbiting each other)
  • · Replies 4 ·
Replies
4
Views
2K
Undergrad Event Horizon and Particle Horizon
  • · Replies 12 ·
Replies
12
Views
5K
Stargazing Astronomers discover 2nd mysterious repeating fast radio burst
  • · Replies 1 ·
Replies
1
Views
3K
Undergrad Solar Images Data: Where to Find?
  • · Replies 6 ·
Replies
6
Views
3K
High School Further collapse of Neutron Stars
  • · Replies 4 ·
Replies
4
Views
2K
Undergrad Life on Neptune: Could Its Ocean Support Complex Life?
  • · Replies 5 ·
Replies
5
Views
5K
Undergrad Calculating STEVE's Height from Two Photos 370km Apart
  • · Replies 116 ·
4
Replies
116
Views
14K
High School Ratio between the sizes of the Observed and the Entire Universe
  • · Replies 7 ·
Replies
7
Views
4K
Undergrad Moon's eccentricity, apogee and perigee
  • · Replies 13 ·
Replies
13
Views
5K
Undergrad Confusion about the math of the Comoving Coordinates
  • · Replies 8 ·
Replies
8
Views
3K
Undergrad Formation of super-massive black holes
  • · Replies 2 ·
Replies
2
Views
2K
Undergrad Is inflation needed to explain uniformity?
  • · Replies 9 ·
Replies
9
Views
3K
High School Another Andromeda-Milky Way "collision" question
  • · Replies 3 ·
Replies
3
Views
2K
Undergrad Gaia Space Telescope and Lagrangian Point 2
  • · Replies 8 ·
Replies
8
Views
12K
Undergrad Sunlight refraction at sunset at different latitudes?
  • · Replies 11 ·
Replies
11
Views
4K
Undergrad Why there is no disturbance in orbital paths?
  • · Replies 4 ·
Replies
4
Views
1K
Undergrad Metric of the Universe and dependence on Cosmological P
  • · Replies 7 ·
Replies
7
Views
2K
Graduate Unification of dark energy and dark matter
  • · Replies 1 ·
Replies
1
Views
2K
Undergrad Why Does the Sun Have an Orbital Period Like a Year?
  • · Replies 11 ·
Replies
11
Views
4K
Undergrad Could Our Universe Be a Mirror Image of an Antimatter Universe?
  • · Replies 6 ·
Replies
6
Views
3K
High School The k term in the Friedmann equation
  • · Replies 2 ·
Replies
2
Views
2K
Undergrad Repurposing Satellites: Maximizing the Lifespan of Space Technology
  • · Replies 6 ·
Replies
6
Views
3K
High School Ideas to protect the Earth from possible asteroid impacts
  • · Replies 59 ·
2
Replies
59
Views
11K
Undergrad Why do we need to unify gravity with the other three forces?
  • · Replies 3 ·
Replies
3
Views
2K
Undergrad The Expanding Universe and a stationary frame of reference
  • · Replies 2 ·
Replies
2
Views
2K
Undergrad Footnote on page 151 of Weinberg's Cosmology book
  • · Replies 2 ·
Replies
2
Views
2K
Undergrad Is there any evidence of a universe expansion jerk
  • · Replies 3 ·
Replies
3
Views
3K
Undergrad Calculating dark energy and matter density
  • · Replies 18 ·
Replies
18
Views
3K
Undergrad Curvature of space in large regions: zero or not?
  • · Replies 9 ·
Replies
9
Views
2K
Undergrad Collision of Milky Way and Andromeda....?
  • · Replies 17 ·
Replies
17
Views
4K
High School Standard candles in a stretching fabric of space
  • · Replies 3 ·
Replies
3
Views
2K
High School Galaxy Collisions & Expansion: What's Going On?
  • · Replies 3 ·
Replies
3
Views
2K
Graduate How Long To 'FreeFall' Into TON 618 From ISCO
  • · Replies 3 ·
Replies
3
Views
9K
High School Meaning of the Abbreviation CCH in Graphic
  • · Replies 2 ·
Replies
2
Views
2K
Undergrad Calculating Velocity of a Ball in a Black Hole's Sphere of Influence
  • · Replies 9 ·
Replies
9
Views
8K
High School The Impact of Expansion on the Observable Universe
  • · Replies 10 ·
Replies
10
Views
3K
High School Why are ds and dω taken as zero in calculating proper distance in cosmology?
  • · Replies 24 ·
Replies
24
Views
4K
Undergrad How does gravity vary in deep mines and interstellar gas?
  • · Replies 6 ·
Replies
6
Views
3K
High School Discover 4 Milky Way Arms: Older Galaxies?
  • · Replies 10 ·
Replies
10
Views
5K
Undergrad Do trojan satellites follow migrating planets?
  • · Replies 16 ·
Replies
16
Views
4K
High School Space Time fabric graphic is misleading
  • · Replies 4 ·
Replies
4
Views
2K
Stargazing Best Telescopes for $1K: Mars, Planets & Night Sky Views
  • · Replies 12 ·
Replies
12
Views
4K
High School Water - Where do you think it came from?
  • · Replies 5 ·
Replies
5
Views
2K
Stargazing Australia's largest optical telescope
  • · Replies 3 ·
Replies
3
Views
2K
High School Searching for the Ninth Planet: Solar System Migration
  • · Replies 5 ·
Replies
5
Views
3K
Undergrad Why do transits of Mercury only occur in May & November?
  • · Replies 4 ·
Replies
4
Views
2K
High School Interstellar Dust: What Blocks Light From Distant Galaxys?
  • · Replies 15 ·
Replies
15
Views
3K
Undergrad Expansion of 3-D positively curved space
  • · Replies 4 ·
Replies
4
Views
1K
Undergrad Black holes with a naked singularity?
  • · Replies 7 ·
Replies
7
Views
4K
High School Why most stars seem to rotate the same direction in a galaxy?
  • · Replies 6 ·
Replies
6
Views
3K
Undergrad Is there a mechanism for creation of negative energy density
  • · Replies 2 ·
Replies
2
Views
7K
Undergrad What is the energy density of spacetime?
  • · Replies 20 ·
Replies
20
Views
4K
High School Why doesn't the moon fall down if it's just a big rock?
  • · Replies 9 ·
Replies
9
Views
3K
Graduate Is there any astro-field that uses QM or GR frequently?
  • · Replies 1 ·
Replies
1
Views
2K
High School Question regarding if curvature is not constant
  • · Replies 6 ·
Replies
6
Views
2K
Undergrad Legendre polynomials in boosted temperature approximation
  • · Replies 8 ·
Replies
8
Views
2K
High School Positive curvature of a 2D surface
  • · Replies 24 ·
Replies
24
Views
4K
Undergrad If a planet struck the sun, would fragments be blasted out?
  • · Replies 7 ·
Replies
7
Views
3K
High School Dark matter research paper question
  • · Replies 8 ·
Replies
8
Views
2K
Undergrad Are there issues with Conformal Gravity as a DM solution?
  • · Replies 5 ·
Replies
5
Views
4K
High School Parallax Limitations: Measuring Distances Miles Away
  • · Replies 4 ·
Replies
4
Views
3K
Undergrad Total number density of galaxies and problematic expression
  • · Replies 15 ·
Replies
15
Views
3K
Undergrad Infer the distance of a closest neighbor galaxy from correlation
  • · Replies 9 ·
Replies
9
Views
2K
Undergrad Why isn't Mercury as red as Mars, even though it has more iron?
  • · Replies 9 ·
Replies
9
Views
4K
Undergrad Would an exploded planet change earths orbit (see graphic)
  • · Replies 12 ·
Replies
12
Views
3K
Stargazing What is the best Dobsonian telescope with a goto feature?
  • · Replies 13 ·
Replies
13
Views
5K
Undergrad What factors determine the composition of a planet's atmosphere?
  • · Replies 4 ·
Replies
4
Views
3K
Undergrad Compute the total stellar mass from a galaxy with Red Giants
  • · Replies 1 ·
Replies
1
Views
2K
Undergrad Colliding black holes: when will linear acceleration end?
  • · Replies 4 ·
Replies
4
Views
2K
Undergrad Restricted three body problem (numerical simulation of gravitational attraction)
  • · Replies 3 ·
Replies
3
Views
7K
Undergrad Gravitational field in the galaxy and Schwarzschild´s time dilation
  • · Replies 3 ·
Replies
3
Views
3K
High School Was the initial condition extremely cold?
  • · Replies 10 ·
Replies
10
Views
2K
Insights Calculating the Spin of Black Hole Sagittarius A* - Comments
  • · Replies 2 ·
Replies
2
Views
4K
Undergrad Matter density in Weinberg's Cosmology book
  • · Replies 5 ·
Replies
5
Views
2K
High School Is one side of the Earth faster at night and slower at daytime?
  • · Replies 10 ·
Replies
10
Views
9K
High School Does galaxy formation conserve mass and angular momentum?
  • · Replies 31 ·
2
Replies
31
Views
5K
Undergrad Is the inflationary universe a scientific theory?
  • · Replies 3 ·
Replies
3
Views
2K
Undergrad Redshift Along Galactic Plane: Study & Research
  • · Replies 5 ·
Replies
5
Views
2K